174 ELECTRON-MICROSCOPIC STRUCTURE OF PROTOZOA 



Text-figure 13. Schematic surface view of parts of three 

 kineties of Colpidium, shown at three different levels. Cilia are 

 indicated as empty circles, with parasomal sacs shown as smaller 

 circles anterior to them. Kinety at left is shown with kinetodesmal 

 fibrils attached. Kinety at center is shown with accompanying 

 longitudinal, transverse, and postciliary fibrils. Kinety at right 

 shows outlines of pellicular alveoli along primary and adjacent 

 secondary meridian; scattered small circles are mucigenic body 

 attachments. From Pitelka, 1961a. 



fibers. The tetrahymenids, however, do not lack fibrillar struc- 

 tures (Text-figs. 12 and 13). The most prominent ones are the 

 kinetodesma (Fig. 72, PL XIX), shown by Metz and Westfall 

 (1954) to consist of short, tapering, striated fibrils arising indivi- 



